Are you using WinSCP internal editor? Are you editing local or remote files? Anyway, there's no such option in WinSCP. It's a normal behaviour that file timestamp updates whenever the file changes.

Whenever I manually correct a typo in an html file and save it, it chenges the "Changed" date to the current date. These are archives which are indexed and the changed date throws the index off. How do I stop it from doing that?
Thanks for your help
Solane